Attachment-plug.



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I ATTACHMENT; PLUG.

(Application 'fllea Dec. 18, 1899.) (N o M o d e I WITNESSES:

' 'Pate nted Feb. I9, 1901.

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1 INVENTOR wlr/ m THE NORRIS runs 00. rho'mumo; wunmuwu. u. c.

Warren starts ATENT tries.

WILLIAM T. PRINGLE, OF LANSDOWNE, PENNSYLVANIA.

ATTA CHM EMT-PLUG.

SPECIFICATION forming part Of Letters Patent No. 668,213, dated February19, 1901.

Application filed December 18, 1899. Serial No. 7&O,688.

To ctZZ whom it may concern:

Be it known that I, WILLIAM 'l. PRINGLE, a citizen of the United States,residing at Lansdowne, in the county of Delaware and State ofPennsylvania, have invented a new and useful Atttachment-Plug, of whichthe following is a specification.

My invention relates to attachment-plugs having contact-plates forconnection and disconnection with the contact-terminals of the line, theobject of my improvement being to afford means for securing thecontact-plates to the non-metallic or insulating part of the plug; andmy invention is especially applicable to plugs in which the insulatingpart is composedof non-workable substance, such as will not readilypermit of threading for cooperation with the screws securing themetallic parts to the insnlating'part. I accomplish this object as shownin the accompanying drawings, in which Figure 1 is a perspective View ofthe insulating-plug with the contact-plates removed. Fig. 2 is a similarview with the contact-plates in place. Fig. 3 is a front elevation ofthe insulating-plug. Fig. 4 is a perspective view of one of thecontactplates. Fig. 5 is a perspective view of one of the keying-blocks.

Similar numerals refer to similar parts throughout the several views.

Referring to the drawings, 1 indicates the insulating portion of theplug; 2, the contactplates, which are secured to the sides of theinsulating-plug. These contact-plates 2 have right-angularly-disposedprojecting members 3, which are adapted to lie upon the opposite sidesof the insulating-block and adjacent to and at right angles with thesides upon which the contact-plates lie. Theseright-angularly-projecting members 3 are adapted to be connected eitherdirectly or through fusewires to the line-terminals. The apertures 6(shown in Figs. 1, 2, and 3) are beveled and extend part way across theside of the plug and are adapted to receive the keying-blocks 7, (shownin Fig. 5,) each of which is provided with a threaded aperture toreceive the screw as means for securing the contactplates 2 to theinsulating-plug. It will be noted that the limit of the aperturedextension 6 prevents the movement of the keyingblock, and consequentlyof the contact memkllo model.)

bers 2, in one direction, while the right-angularly-projecting members 3prevent the movement of the plates 2 in the opposite direction. Thus isafforded convenient and efficient means for securing the plates to theinsulating-plug where it is impossible to work screwthreads in thematerial of said insulatingplug. This is both novel and useful in Viewof the fact that the material heretofore composing said insulatingportion of the plug has been expensive to produce in the form requiredand having to be of such composition as would permit ofworkingscrew-threadsinto the same has consequently been subject to theinjurious effects of heavy currents of electricity.

The use of porcelain or an equivalent ma.- terial, which is otherwiseperfectly adapted as an insulator, has been impracticable heretoforebecause of the difficulty of securing the metallic parts thereto.

While I have shown a specific and convenient form of aperture andkeying-block, it is obvious that these may be varied and still be withinthe scope of my invention.

WVhat I claim is- 1. In an attachment-plug the combination of conductivecontact-plates and a non-conducting part, the non-conducting partprovided with apertures in its sides, keying-nuts adapted to occupy saidapertures with limited movement in one direction to cooperate in securing the contact-plates, the contact-plates provided with rightangularly projecting members to prevent the movement of the plates inthe opposite direction, substantially as described.

2. In an attaohment-plug, the combination of contact-plates, aninsulating-block having upon its opposite sides channels of limitedextension, keying-nuts residing in the channels limited as to theirmovement in one direction by the limit of the channel and as to theother direction by the contact-plate secured-thereto, substantially asdescribed.

3. In an attachment-plug the combination of contact-plates and anon-conductive block with mortises extending part way across itsopposite sides, keying-nuts secured in said mortises to cooperate insecuring the contactplates, the contact-plates havingright-angularly-projectin g members adapted to lock the ofcontact-plates, an insulating-block having apertures therein, keyingmembers residing in the apertures, limited as to their respectivemovements in one direction by the limit of the apertures and in theother direction by the contact-plates secured thereto, substantially asdescribed.

WM. T. PRINGLE.

Witnesses:

JNo. STOKES ADAMS, MAE HOFFMANN.

